The most commonly used voltage regulator design comprises a synchronous-buck topology. In conventional synchronous-buck power converters, an input voltage (VIN) is stepped down to an operating voltage (VOUT) for a microprocessor (or a similar variable load). The converter controls VOUT by controlling the duty cycle of two output power switches. Typically, the output power switches are Metal Oxide Semiconductor Field-Effect Transistors, or MOSFETs.
The conventional synchronous converter operates with a switching “dead-time” interval between the upper and lower power switches. This dead-time interval prevents short-circuiting of the input VIN if both the upper and lower power switches were to be turned on simultaneously. During the dead-time, the main inductor current flows via a body diode of at least one of the upper and the lower power switches, commonly known as body diode conduction. Body diode conduction leads to substantial power loss due to (1) a relatively high voltage drop across the P-N junction of the power switches (when compared with the MOSFET voltage drop) and (2) a “reverse recovery loss” associated with the stored charge. Accordingly, there is a need for improvements in dead-time transition adjustments for synchronous power converters.